Study on the Corrosion Behavior In Vitro and Mechanical Properties of the FHA Coated Mg-Zn-Zr Alloy

The fluorine-doped hydroxyapatite (FHA) coating on the surface of Mg-3wt%Zn-0.8wt%Zr alloy was prepared using a chemical treatment method. The standard tensile samples of coated and uncoated Mg alloy were immersed in the SBF respectively for 1,3,5,10,20 and 30 days. The effect of the FHA coating on corrosion behavior in vitro and mechanical properties of the Mg-Zn-Zr alloy was investigated. Based on the losing weight and the max corrosion depth of the samples, the corrosion rate can be calculated. According to the weightlessness curve of samples, the average corrosion rate of the bare alloy, the alloy of MgF2 coating and the alloy of FHA coating were 4.13mm / y, 1.51mm / y and 0.86mm / y within 30 days in vitro, respectively. It can be seen that the significant difference of mechanical properties between the coated and uncoated samples with the increase of immersing time. This fully revealed that the FHA coating on the Mg-Zn-Zr alloy is beneficial to improve its corrosion resistance.